The major purpose of this study is to advance understanding of the factors which predict exits and reentries into homelessness among the homeless with and without serious mental illness, knowledge which can inform efforts to resolve the condition of homelessness. A secondary purpose is to profile the pre-homeless backgrounds and the contexts in which such individuals become homeless, to contribute to knowledge of who is at-risk for homelessness and to aid future efforts to prevent homelessness. A representative sample of 1500 homeless adults in two Los Angeles sites will be surveyed. From this cross-sectional sample, a panel of 480 will be selected for a 2 year follow-up survey, with additional ethnographic data collected on 120 of these. The specific aims of the study are: 1. To retrospectively characterize the pre-homeless backgrounds and contexts of first becoming homeless among those with and without serious mental illness, and to examine the association between these pre-homeless factors and homeless experiences. 2. To prospectively identify factors that predict course of homelessness (probability of exits and reentries over time) among those with and without serious mental illness. 3. To investigate the extent to which homeless exits and reentries predict subsequent changes,in access to resources, functioning, subsistence patterns, and satisfaction with living environment. 4. To identify predictors of satisfaction with permanent housing situations among pr.eviously homeless individuals with and without serious mental illness.